skip to main content

Title: Above-bandgap optical properties of biaxially strained GeSn alloys grown by molecular beam epitaxy

The complex dielectric function of biaxially strained Ge{sub 1−x}Sn{sub x} (0 ≤ x ≤ 0.17) alloys grown on Ge (100) has been determined by spectroscopic ellipsometry from 1.2 to 4.7 eV. The effect of substitutional Sn incorporation and the epitaxial strain on the energy transitions E{sub 1}, E{sub 1} + Δ{sub 1}, E{sub 0}′, and E{sub 2} of GeSn alloys is investigated. Our results indicate that the strained GeSn alloys show Ge-like electronic bandstructure with all the transitions shifted downward due to the alloying of Sn. The strain dependence of E{sub 1} and E{sub 1} + Δ{sub 1} transitions is explained using the deformation potential theory, and values of −5.4 ± 0.4 eV and 3.8 ± 0.5 eV are obtained for the hydrostatic and shear deformation potentials, respectively.
Authors:
; ; ;  [1] ;  [2]
  1. Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore)
  2. Department of Physics, National University of Singapore, Singapore 117551 (Singapore)
Publication Date:
OSTI Identifier:
22275723
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 2; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALLOYS; DIELECTRIC MATERIALS; ELLIPSOMETRY; GERMANIUM; MOLECULAR BEAM EPITAXY; OPTICAL PROPERTIES; STRAINS; TIN